The present invention, in some embodiments thereof, relates to methods and devices for producing electricity from high altitude wind sources. In some embodiments, a plurality of unpiloted zeppelins or dirigibles with hollow cavities is employed to convert strong wind sources into usable electricity.
One of the most basic necessities form mankind is energy. Energy sources such as coal, oil, and natural gas, while abundant and in great use, are of necessity of finite amount. For decades, great efforts have been undertaken to develop “renewable” energy sources such as wind, wave, and solar. The results have been mixed, and today the percentage of energy used in the United States which is not based on some form of carbon is still in the single digits as a percentage of total power production. This situation is in need of redress.
While there are active wind farms in the United States, they have not come without controversy and problems. Legal fights have been associated with location selection of wind farms: oftentimes, the optimal place to put huge wind turbines is the least popular due to aesthetic, health, or land issues. Additionally, even working wind farms experience problems. During a particularly hot Texas summer in 2011, wind turbines succeeded in producing only a fraction of their rated power output. Very thin hot air apparently was unable to turn the turbine rotor blades in a manner that could yield higher amounts of electricity.
One approach to addressing both the land use issue as well as the efficiency of electrical generation is to move turbines higher in the atmosphere. By doing so, one has access to higher speed winds while at the same time significantly freeing up land from fixed, massive vertical turbines.
U.S. Pat. No. 4,659,940 to Shepard discloses a method and apparatus for the production of electrical power from high altitude winds. A kitecraft secured to a ground tether supports a cylindrical drum rotatable about a horizontal shaft. The drum comprises a plurality of wheels interconnected by airfoils positioned about the cylindrical surface of the drum. Wind action on the airfoils rotates the drum about the horizontal shaft and turns generators to provide electrical power. The kitecraft and drum assembly is constructed to the maximum practical extent from tension members to reduce weight.
U.S. patent application Ser. No. 10/064,806 to Roberts & Shepard teaches tethered wind supported flying electric generators (FEGS) capable of deriving power from high altitude winds that are held stable in precisely controlled positions in spite of wind fluctuations and temporary wind absence. FEGs are windmill-like rotorcraft, somewhat resembling helicopters, which are raised to a strong wind altitude using electric motors driving the rotors, each craft powered through tethers) from a corresponding single point on the ground. Then the rotorcraft is tilted at an angle, the wind turns the rotors, and thus keeps the craft aloft and sends power back to the ground, now using the motors as generators. Precise craft geographic position, altitude and attitude are determined by various sensing means. Computer logic, provided with this information and wind and other weather data, command individual craft control functions and thus may also command arrays of these FEGs to maintain precise geographic and altitude locations or be grounded under tether winch control when necessary.
U.S. Pat. No. 4,572,972 to Shepard describes a wind-operated power-generating module for operation at high altitudes such as 1000 meters comprising a frame structure mounting a pair of vertically-separated parallel shafts around which pass endless belts supporting a series of parallel, elongate wing-like elements for movement around a closed path including the parallel shafts. Wind flow drives these elements around the closed path, to enable electrical power to be generated, and also provides lift to hold the module up at the appropriate high altitude. A number of such modules are tethered in fixed positions in the sky, and are controllable as is appropriate to accommodate changing wind conditions.
U.S. patent application Ser. No. 12/711,847 to Tigner teaches power generation systems comprising an array or rotary-wing kites that may be coupled to ground-based spools via tethers. The rotational motion of the spools may be converted into electrical energy via one or more generators.
U.S. Pat. No. 6,254,034 to Carpenter describes tethered aircraft blown by wind downwind at a controlled rate for maximal mechanical energy. Travel downwind allows for generation of energy into a spooling system used to release a tether wire attached to the aircraft. After downwind travel, the aircraft is brought again upwind at a later time so as to repeat the energy-generation process.